US5821280A - Process for producing conductive composition for biological electrode - Google Patents
Process for producing conductive composition for biological electrode Download PDFInfo
- Publication number
- US5821280A US5821280A US08/687,920 US68792096A US5821280A US 5821280 A US5821280 A US 5821280A US 68792096 A US68792096 A US 68792096A US 5821280 A US5821280 A US 5821280A
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- United States
- Prior art keywords
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- weight
- mixture
- acid
- conductive composition
- Prior art date
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- Expired - Fee Related
Links
- 239000000203 mixture Substances 0.000 title claims abstract description 127
- 238000000034 method Methods 0.000 title claims abstract description 22
- 230000008569 process Effects 0.000 title claims abstract description 18
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims abstract description 90
- 239000004909 Moisturizer Substances 0.000 claims abstract description 37
- 230000001333 moisturizer Effects 0.000 claims abstract description 37
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 34
- 239000002253 acid Substances 0.000 claims abstract description 24
- 238000002156 mixing Methods 0.000 claims abstract description 22
- 150000001875 compounds Chemical class 0.000 claims abstract description 20
- 239000003431 cross linking reagent Substances 0.000 claims abstract description 16
- 239000003505 polymerization initiator Substances 0.000 claims abstract description 10
- 238000010438 heat treatment Methods 0.000 claims abstract description 7
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- 239000007795 chemical reaction product Substances 0.000 claims abstract description 3
- 230000001737 promoting effect Effects 0.000 claims abstract description 3
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- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 claims description 49
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 49
- 239000000178 monomer Substances 0.000 claims description 43
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 claims description 36
- 239000004310 lactic acid Substances 0.000 claims description 22
- 235000014655 lactic acid Nutrition 0.000 claims description 22
- ODHCTXKNWHHXJC-VKHMYHEASA-N 5-oxo-L-proline Chemical compound OC(=O)[C@@H]1CCC(=O)N1 ODHCTXKNWHHXJC-VKHMYHEASA-N 0.000 claims description 19
- 229940079889 pyrrolidonecarboxylic acid Drugs 0.000 claims description 19
- 229910052757 nitrogen Inorganic materials 0.000 claims description 15
- ZIUHHBKFKCYYJD-UHFFFAOYSA-N n,n'-methylenebisacrylamide Chemical compound C=CC(=O)NCNC(=O)C=C ZIUHHBKFKCYYJD-UHFFFAOYSA-N 0.000 claims description 14
- 239000003999 initiator Substances 0.000 claims description 13
- XMLYCEVDHLAQEL-UHFFFAOYSA-N 2-hydroxy-2-methyl-1-phenylpropan-1-one Chemical compound CC(C)(O)C(=O)C1=CC=CC=C1 XMLYCEVDHLAQEL-UHFFFAOYSA-N 0.000 claims description 9
- 239000012956 1-hydroxycyclohexylphenyl-ketone Substances 0.000 claims description 6
- OZAIFHULBGXAKX-UHFFFAOYSA-N 2-(2-cyanopropan-2-yldiazenyl)-2-methylpropanenitrile Chemical group N#CC(C)(C)N=NC(C)(C)C#N OZAIFHULBGXAKX-UHFFFAOYSA-N 0.000 claims description 6
- LEJBBGNFPAFPKQ-UHFFFAOYSA-N 2-(2-prop-2-enoyloxyethoxy)ethyl prop-2-enoate Chemical compound C=CC(=O)OCCOCCOC(=O)C=C LEJBBGNFPAFPKQ-UHFFFAOYSA-N 0.000 claims description 6
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 claims description 6
- MQDJYUACMFCOFT-UHFFFAOYSA-N bis[2-(1-hydroxycyclohexyl)phenyl]methanone Chemical compound C=1C=CC=C(C(=O)C=2C(=CC=CC=2)C2(O)CCCCC2)C=1C1(O)CCCCC1 MQDJYUACMFCOFT-UHFFFAOYSA-N 0.000 claims description 6
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 claims description 5
- UICXTANXZJJIBC-UHFFFAOYSA-N 1-(1-hydroperoxycyclohexyl)peroxycyclohexan-1-ol Chemical compound C1CCCCC1(O)OOC1(OO)CCCCC1 UICXTANXZJJIBC-UHFFFAOYSA-N 0.000 claims description 3
- XMNIXWIUMCBBBL-UHFFFAOYSA-N 2-(2-phenylpropan-2-ylperoxy)propan-2-ylbenzene Chemical compound C=1C=CC=CC=1C(C)(C)OOC(C)(C)C1=CC=CC=C1 XMNIXWIUMCBBBL-UHFFFAOYSA-N 0.000 claims description 3
- JAHNSTQSQJOJLO-UHFFFAOYSA-N 2-(3-fluorophenyl)-1h-imidazole Chemical compound FC1=CC=CC(C=2NC=CN=2)=C1 JAHNSTQSQJOJLO-UHFFFAOYSA-N 0.000 claims description 3
- WFUGQJXVXHBTEM-UHFFFAOYSA-N 2-hydroperoxy-2-(2-hydroperoxybutan-2-ylperoxy)butane Chemical compound CCC(C)(OO)OOC(C)(CC)OO WFUGQJXVXHBTEM-UHFFFAOYSA-N 0.000 claims description 3
- JJRDRFZYKKFYMO-UHFFFAOYSA-N 2-methyl-2-(2-methylbutan-2-ylperoxy)butane Chemical compound CCC(C)(C)OOC(C)(C)CC JJRDRFZYKKFYMO-UHFFFAOYSA-N 0.000 claims description 3
- RDFQSFOGKVZWKF-UHFFFAOYSA-N 3-hydroxy-2,2-dimethylpropanoic acid Chemical compound OCC(C)(C)C(O)=O RDFQSFOGKVZWKF-UHFFFAOYSA-N 0.000 claims description 3
- FQMIAEWUVYWVNB-UHFFFAOYSA-N 3-prop-2-enoyloxybutyl prop-2-enoate Chemical compound C=CC(=O)OC(C)CCOC(=O)C=C FQMIAEWUVYWVNB-UHFFFAOYSA-N 0.000 claims description 3
- DBCAQXHNJOFNGC-UHFFFAOYSA-N 4-bromo-1,1,1-trifluorobutane Chemical compound FC(F)(F)CCCBr DBCAQXHNJOFNGC-UHFFFAOYSA-N 0.000 claims description 3
- JHWGFJBTMHEZME-UHFFFAOYSA-N 4-prop-2-enoyloxybutyl prop-2-enoate Chemical compound C=CC(=O)OCCCCOC(=O)C=C JHWGFJBTMHEZME-UHFFFAOYSA-N 0.000 claims description 3
- FIHBHSQYSYVZQE-UHFFFAOYSA-N 6-prop-2-enoyloxyhexyl prop-2-enoate Chemical compound C=CC(=O)OCCCCCCOC(=O)C=C FIHBHSQYSYVZQE-UHFFFAOYSA-N 0.000 claims description 3
- HRPVXLWXLXDGHG-UHFFFAOYSA-N Acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 claims description 3
- 239000004342 Benzoyl peroxide Substances 0.000 claims description 3
- OMPJBNCRMGITSC-UHFFFAOYSA-N Benzoylperoxide Chemical compound C=1C=CC=CC=1C(=O)OOC(=O)C1=CC=CC=C1 OMPJBNCRMGITSC-UHFFFAOYSA-N 0.000 claims description 3
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 claims description 3
- 239000005977 Ethylene Substances 0.000 claims description 3
- YIVJZNGAASQVEM-UHFFFAOYSA-N Lauroyl peroxide Chemical compound CCCCCCCCCCCC(=O)OOC(=O)CCCCCCCCCCC YIVJZNGAASQVEM-UHFFFAOYSA-N 0.000 claims description 3
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 claims description 3
- WHNWPMSKXPGLAX-UHFFFAOYSA-N N-Vinyl-2-pyrrolidone Chemical compound C=CN1CCCC1=O WHNWPMSKXPGLAX-UHFFFAOYSA-N 0.000 claims description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 3
- DAKWPKUUDNSNPN-UHFFFAOYSA-N Trimethylolpropane triacrylate Chemical compound C=CC(=O)OCC(CC)(COC(=O)C=C)COC(=O)C=C DAKWPKUUDNSNPN-UHFFFAOYSA-N 0.000 claims description 3
- OKKRPWIIYQTPQF-UHFFFAOYSA-N Trimethylolpropane trimethacrylate Chemical compound CC(=C)C(=O)OCC(CC)(COC(=O)C(C)=C)COC(=O)C(C)=C OKKRPWIIYQTPQF-UHFFFAOYSA-N 0.000 claims description 3
- HVVWZTWDBSEWIH-UHFFFAOYSA-N [2-(hydroxymethyl)-3-prop-2-enoyloxy-2-(prop-2-enoyloxymethyl)propyl] prop-2-enoate Chemical compound C=CC(=O)OCC(CO)(COC(=O)C=C)COC(=O)C=C HVVWZTWDBSEWIH-UHFFFAOYSA-N 0.000 claims description 3
- MPIAGWXWVAHQBB-UHFFFAOYSA-N [3-prop-2-enoyloxy-2-[[3-prop-2-enoyloxy-2,2-bis(prop-2-enoyloxymethyl)propoxy]methyl]-2-(prop-2-enoyloxymethyl)propyl] prop-2-enoate Chemical compound C=CC(=O)OCC(COC(=O)C=C)(COC(=O)C=C)COCC(COC(=O)C=C)(COC(=O)C=C)COC(=O)C=C MPIAGWXWVAHQBB-UHFFFAOYSA-N 0.000 claims description 3
- RWCCWEUUXYIKHB-UHFFFAOYSA-N benzophenone Chemical compound C=1C=CC=CC=1C(=O)C1=CC=CC=C1 RWCCWEUUXYIKHB-UHFFFAOYSA-N 0.000 claims description 3
- 239000012965 benzophenone Substances 0.000 claims description 3
- 235000019400 benzoyl peroxide Nutrition 0.000 claims description 3
- LDHQCZJRKDOVOX-NSCUHMNNSA-N crotonic acid Chemical compound C\C=C\C(O)=O LDHQCZJRKDOVOX-NSCUHMNNSA-N 0.000 claims description 3
- 125000000058 cyclopentadienyl group Chemical group C1(=CC=CC1)* 0.000 claims description 3
- LSXWFXONGKSEMY-UHFFFAOYSA-N di-tert-butyl peroxide Chemical compound CC(C)(C)OOC(C)(C)C LSXWFXONGKSEMY-UHFFFAOYSA-N 0.000 claims description 3
- 125000004386 diacrylate group Chemical group 0.000 claims description 3
- TVWTZAGVNBPXHU-FOCLMDBBSA-N dioctyl (e)-but-2-enedioate Chemical compound CCCCCCCCOC(=O)\C=C\C(=O)OCCCCCCCC TVWTZAGVNBPXHU-FOCLMDBBSA-N 0.000 claims description 3
- VFHVQBAGLAREND-UHFFFAOYSA-N diphenylphosphoryl-(2,4,6-trimethylphenyl)methanone Chemical compound CC1=CC(C)=CC(C)=C1C(=O)P(=O)(C=1C=CC=CC=1)C1=CC=CC=C1 VFHVQBAGLAREND-UHFFFAOYSA-N 0.000 claims description 3
- ZSWFCLXCOIISFI-UHFFFAOYSA-N endo-cyclopentadiene Natural products C1C=CC=C1 ZSWFCLXCOIISFI-UHFFFAOYSA-N 0.000 claims description 3
- STVZJERGLQHEKB-UHFFFAOYSA-N ethylene glycol dimethacrylate Substances CC(=C)C(=O)OCCOC(=O)C(C)=C STVZJERGLQHEKB-UHFFFAOYSA-N 0.000 claims description 3
- 239000000374 eutectic mixture Substances 0.000 claims description 3
- FQPSGWSUVKBHSU-UHFFFAOYSA-N methacrylamide Chemical compound CC(=C)C(N)=O FQPSGWSUVKBHSU-UHFFFAOYSA-N 0.000 claims description 3
- YDKNBNOOCSNPNS-UHFFFAOYSA-N methyl 1,3-benzoxazole-2-carboxylate Chemical compound C1=CC=C2OC(C(=O)OC)=NC2=C1 YDKNBNOOCSNPNS-UHFFFAOYSA-N 0.000 claims description 3
- LVHBHZANLOWSRM-UHFFFAOYSA-N methylenebutanedioic acid Natural products OC(=O)CC(=C)C(O)=O LVHBHZANLOWSRM-UHFFFAOYSA-N 0.000 claims description 3
- SLCVBVWXLSEKPL-UHFFFAOYSA-N neopentyl glycol Chemical compound OCC(C)(C)CO SLCVBVWXLSEKPL-UHFFFAOYSA-N 0.000 claims description 3
- 229940117969 neopentyl glycol Drugs 0.000 claims description 3
- 229940068918 polyethylene glycol 400 Drugs 0.000 claims description 3
- 150000003839 salts Chemical class 0.000 claims description 3
- GJBRNHKUVLOCEB-UHFFFAOYSA-N tert-butyl benzenecarboperoxoate Chemical compound CC(C)(C)OOC(=O)C1=CC=CC=C1 GJBRNHKUVLOCEB-UHFFFAOYSA-N 0.000 claims description 3
- CIHOLLKRGTVIJN-UHFFFAOYSA-N tert‐butyl hydroperoxide Chemical compound CC(C)(C)OO CIHOLLKRGTVIJN-UHFFFAOYSA-N 0.000 claims description 3
- 229910052719 titanium Inorganic materials 0.000 claims description 3
- 239000010936 titanium Substances 0.000 claims description 3
- LDHQCZJRKDOVOX-UHFFFAOYSA-N trans-crotonic acid Natural products CC=CC(O)=O LDHQCZJRKDOVOX-UHFFFAOYSA-N 0.000 claims description 3
- KWVGIHKZDCUPEU-UHFFFAOYSA-N 2,2-dimethoxy-2-phenylacetophenone Chemical group C=1C=CC=CC=1C(OC)(OC)C(=O)C1=CC=CC=C1 KWVGIHKZDCUPEU-UHFFFAOYSA-N 0.000 claims description 2
- UHFFVFAKEGKNAQ-UHFFFAOYSA-N 2-benzyl-2-(dimethylamino)-1-(4-morpholin-4-ylphenyl)butan-1-one Chemical compound C=1C=C(N2CCOCC2)C=CC=1C(=O)C(CC)(N(C)C)CC1=CC=CC=C1 UHFFVFAKEGKNAQ-UHFFFAOYSA-N 0.000 claims description 2
- 229920000642 polymer Polymers 0.000 claims description 2
- DZSVIVLGBJKQAP-UHFFFAOYSA-N 1-(2-methyl-5-propan-2-ylcyclohex-2-en-1-yl)propan-1-one Chemical compound CCC(=O)C1CC(C(C)C)CC=C1C DZSVIVLGBJKQAP-UHFFFAOYSA-N 0.000 claims 1
- 239000000243 solution Substances 0.000 abstract description 171
- 239000007787 solid Substances 0.000 abstract description 11
- 238000005266 casting Methods 0.000 abstract description 8
- 238000002347 injection Methods 0.000 abstract description 7
- 239000007924 injection Substances 0.000 abstract description 7
- 238000000465 moulding Methods 0.000 abstract description 3
- 238000006116 polymerization reaction Methods 0.000 description 44
- 230000002269 spontaneous effect Effects 0.000 description 21
- 239000000499 gel Substances 0.000 description 19
- 238000003756 stirring Methods 0.000 description 15
- 238000004132 cross linking Methods 0.000 description 14
- 238000001816 cooling Methods 0.000 description 10
- 238000011156 evaluation Methods 0.000 description 10
- 238000001879 gelation Methods 0.000 description 10
- 238000009835 boiling Methods 0.000 description 8
- 238000004090 dissolution Methods 0.000 description 8
- 239000001521 potassium lactate Substances 0.000 description 8
- 235000011085 potassium lactate Nutrition 0.000 description 8
- 229960001304 potassium lactate Drugs 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 239000001540 sodium lactate Substances 0.000 description 7
- 235000011088 sodium lactate Nutrition 0.000 description 7
- 229940005581 sodium lactate Drugs 0.000 description 7
- CRPCXAMJWCDHFM-UHFFFAOYSA-M sodium;5-oxopyrrolidine-2-carboxylate Chemical compound [Na+].[O-]C(=O)C1CCC(=O)N1 CRPCXAMJWCDHFM-UHFFFAOYSA-M 0.000 description 7
- 239000000047 product Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 5
- 229910052753 mercury Inorganic materials 0.000 description 5
- 238000006386 neutralization reaction Methods 0.000 description 5
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 239000003792 electrolyte Substances 0.000 description 4
- 230000000977 initiatory effect Effects 0.000 description 4
- 229920001296 polysiloxane Polymers 0.000 description 4
- 206010040880 Skin irritation Diseases 0.000 description 3
- 238000001704 evaporation Methods 0.000 description 3
- 230000008020 evaporation Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 230000002787 reinforcement Effects 0.000 description 3
- 230000036556 skin irritation Effects 0.000 description 3
- 231100000475 skin irritation Toxicity 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- 229920000536 2-Acrylamido-2-methylpropane sulfonic acid Polymers 0.000 description 2
- XHZPRMZZQOIPDS-UHFFFAOYSA-N 2-Methyl-2-[(1-oxo-2-propenyl)amino]-1-propanesulfonic acid Chemical compound OS(=O)(=O)CC(C)(C)NC(=O)C=C XHZPRMZZQOIPDS-UHFFFAOYSA-N 0.000 description 2
- 241000209149 Zea Species 0.000 description 2
- 235000005824 Zea mays ssp. parviglumis Nutrition 0.000 description 2
- 235000002017 Zea mays subsp mays Nutrition 0.000 description 2
- 239000002390 adhesive tape Substances 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 235000005822 corn Nutrition 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 230000009969 flowable effect Effects 0.000 description 2
- 239000012299 nitrogen atmosphere Substances 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- 239000011780 sodium chloride Substances 0.000 description 2
- 230000002459 sustained effect Effects 0.000 description 2
- 238000009281 ultraviolet germicidal irradiation Methods 0.000 description 2
- DSPDJPFEBQTXDO-UHFFFAOYSA-N 1-[2-(3-pyrrolidin-1-ylprop-1-ynyl)piperidin-1-yl]ethanone Chemical compound CC(=O)N1CCCCC1C#CCN1CCCC1 DSPDJPFEBQTXDO-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 208000010201 Exanthema Diseases 0.000 description 1
- JVTAAEKCZFNVCJ-UHFFFAOYSA-M Lactate Chemical compound CC(O)C([O-])=O JVTAAEKCZFNVCJ-UHFFFAOYSA-M 0.000 description 1
- 229910021607 Silver chloride Inorganic materials 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 239000012298 atmosphere Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000002565 electrocardiography Methods 0.000 description 1
- 238000000537 electroencephalography Methods 0.000 description 1
- 238000002567 electromyography Methods 0.000 description 1
- 201000005884 exanthem Diseases 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 230000009545 invasion Effects 0.000 description 1
- 235000015110 jellies Nutrition 0.000 description 1
- 239000008274 jelly Substances 0.000 description 1
- 229940001447 lactate Drugs 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000033001 locomotion Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- PHZLMBHDXVLRIX-UHFFFAOYSA-M potassium lactate Chemical compound [K+].CC(O)C([O-])=O PHZLMBHDXVLRIX-UHFFFAOYSA-M 0.000 description 1
- WKHCFXKQKDNLEB-DFWYDOINSA-M potassium;(2s)-5-oxopyrrolidine-2-carboxylate Chemical compound [K+].[O-]C(=O)[C@@H]1CCC(=O)N1 WKHCFXKQKDNLEB-DFWYDOINSA-M 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 206010037844 rash Diseases 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 description 1
- 230000037380 skin damage Effects 0.000 description 1
- 230000000638 stimulation Effects 0.000 description 1
- 150000005846 sugar alcohols Polymers 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F20/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride, ester, amide, imide or nitrile thereof
- C08F20/02—Monocarboxylic acids having less than ten carbon atoms, Derivatives thereof
- C08F20/04—Acids, Metal salts or ammonium salts thereof
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2/00—Processes of polymerisation
- C08F2/46—Polymerisation initiated by wave energy or particle radiation
- C08F2/48—Polymerisation initiated by wave energy or particle radiation by ultraviolet or visible light
Definitions
- This invention relates to a conductive composition to be located between the skin and an electrode element when a biological electrode is applied to the skin.
- a biological electrode consists of an electrode element made of silver, silver/silver chloride, carbon and the like and a conductive composition connecting the electrode element to the skin and is applied to the surface of a living body in order to output some bioelectrical phenomena (e.g., electrocardiogram, electromyogram, etc.) or electrically stimulate the living body.
- bioelectrical phenomena e.g., electrocardiogram, electromyogram, etc.
- horny layer Normal human skin has an external layer called "horny layer" which protects the living body against the invasion of various foreign factors.
- horny layer When the skin is contacted with the dry atmosphere, the moisture is lost from the horny layer. Also, the moisture content in the horny layer is reduced as aging proceeds. In such cases, the electrical resistance of the horny layer is elevated.
- the surface of the skin is not smooth but uneven and has a complicated shape, for example, being curved.
- conductive compositions in the form of liquid, jelly or gel are generally employed in biological electrodes so as to reduce the skin resistance between the living body and the electrode element.
- These conductive compositions contain a large amount of water and/or electrolytes such as NaCl or KCl which are externally absorbed by the skin horny layer to thereby reduce the skin resistance.
- a conductive composition per se has a low viscosity and a high flowability, which makes it difficult to stably sustain the conductive composition between the electrode element and the skin for a prolonged period of time.
- the electrode element should be provided with a containment space or a holding means such as sponge for supporting the conductive composition.
- the electrode element should be further provided with an adhesive tape for fixing it on the skin surface. When an adhesive tape is used, however, repeated application and removal of the electrode element cause mechanical damage to the skin.
- the conductive composition When an electrode element is applied to the skin surface for a long time via such a conductive composition in an ICU, Holter's electrocardiography, etc., the conductive composition bears mechanical load due to body motion and external pressure. The conductive composition leaks from the electrode element to cause detachment of the electrode element or unstable contact of the electrode element with the skin, thus making it impossible to record the biological signals.
- such a conductive composition is dried during application due to the evaporation of the moisture contained therein.
- the skin resistance is elevated, thereby making the record of the biological signals unstable.
- the evaporation of the moisture contained in the conductive composition causes an increase in the chlorine ion concentration in the conductive composition, which induces skin irritation.
- such a conductive composition remains on the skin and causes rash.
- Electrodes usable repeatedly and so-called disposable ones which are thrown away after being used once.
- a conductive composition is applied to the skin immediately before use.
- a conductive composition has been preliminarily filled or incorporated into the electrode in many cases so that they can be easily applied.
- an electrode element of the latter type should have a complicated structure as a whole with taking the use and storage thereof into consideration.
- a feedstock solution is first prepared and poured into a mold followed by UV irradiation or heating for initiating crosslinking polymerization.
- the acrylic acid monomer undergoes spontaneous polymerization immediately after the feedstock solution is prepared owing to a moisturizer contained in the feedstock solution.
- the moisturizer has a function of reducing the pH value at which spontaneous polymerization of the acrylic acid monomer is initiated and further the acrylic acid becomes unstable, although the acrylic acid monomer generally undergoes spontaneous polymerization due to unstable double bonds when the pH value is high.
- the moisturizer When the moisturizer is added at the higher ratio, then the above-mentioned phenomenon occurs at the higher frequency.
- the feedstock solution becomes more viscous and less flowable and gelation occurs before the initiation of the crosslinking polymerization.
- the feedstock solution can be hardly poured into a mold and thus short shot of the feedstock solution makes it impossible to mold the solid gel by casting or injection.
- the crosslinking polymerization cannot uniformly proceed and there remain partially unpolymerized monomers, thus causing skin irritation.
- the occurrence of the spontaneous polymerization makes the feedstock solution chemically unstable and thus shortens its pot life. In such a case, it is difficult to prepare the feedstock solution in a large batch, which brings about a problem that mass production on, for example, an automated line can be hardly performed.
- the spontaneous polymerization of the feedstock solution causes an increase in the viscosity of the feedstock solution and makes it chemically unstable. As a result, the gelation proceeds and the application of the feedstock solution becomes difficult.
- An object of the present invention is to provide a process for producing a conductive composition wherein casting or injection is performed while maintaining the flowability of the feedstock solution to thereby mold the feedstock solution into a solid gel of a desired shape.
- the present invention relates to a process for producing a conductive gel composition for a biological electrode having a function of electrically and physically connecting a living body to an electrode element and comprising the following components:
- reaction product which is a moisturizer serving as a plasticizer and having a function of supplementing and promoting the physiological humidifying function of the horny layer;
- the unsaturated compound of the component (1) contained in the conductive composition of the present invention is selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, itaconic acid, acrylamide, methacrylamide, 2-acrylamido-2-methylpropane-sulfonic acid and salts thereof, and mixtures thereof, an acrylic acid/vinylpyrrolidone mixture, a vinyl acetate/ethylene mixture and a vinyl acetate/dioctyl maleate mixture.
- the acid employed as the component (2), which reacts with NaOH or KOH to give a moisturizer is lactic acid, pyrrolidonecarboxylic acid or a combination thereof.
- such a moisturizer can elevate the conductivity of the conductive composition per se without adding any electrolyte (NaCl, KCl, etc.), different from the conventional cases wherein nonionic polyhydric alcohols are added as a plasticizer.
- the moisturizer When the moisturizer penetrates into the skin horny layer, the water contained in the tissue binds to the moisturizer to thereby improve the humidifying properties of the horny layer per se.
- the moisture content in the skin horny layer can be elevated.
- An increase in the moisture content in the skin horny layer results in a decrease in the electrical resistance of the horny layer and, in its turn, reduces the impedance of the electrode against the skin.
- the moisturizer contributes to the reduction of the impedance to the skin, the moisture content in the conductive composition can be regulated to a low level and thus the stickiness thereof can be improved. As a result, the evaporation of the moisture from the composition can be suppressed during storage or application.
- the conductive composition is free from any skin troubles caused by the percutaneous absorption of the excessive water or electrolytes, etc.
- the moisturizer also has an effect of imparting stickiness.
- the stickiness of the composition to the skin can be further strengthened by adding it.
- the stickiness of the composition to the skin can be arbitrarily controlled easily by varying its content. That is to say, the moisturizer has four functions (i.e., as a plasticizer, as an electrolyte, as an agent for increasing the moisture content in the horny layer and as a an agent of imparting stickiness).
- the moisturizer has four functions (i.e., as a plasticizer, as an electrolyte, as an agent for increasing the moisture content in the horny layer and as a an agent of imparting stickiness).
- the photopolymerization initiator of the component (5) is selected from the group consisting of benzildimethyl-ketal, 1-hydroxycyclohexyl phenyl ketone, an eutectic mixture of 1-hydroxycyclohexyl phenyl ketone with benzophenone, 2-methyl-1- 4-(methylthio)phenyl!-2-morpholino-propanone-1, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-hydroxy-2-methyl-1-phenylpropan-1-one, a mixture of 2-hydroxy-2-methyl-1-phenylpropan-1-one with 2,4,6-trimethylbenzoyldiphenylphosphine oxide, a mixture of 2-hydroxy-2-methyl-1-phenylpropan-1-one with bisacylphosphine oxide, 1- 4-(2-hydroxyethoxy)phenyl!-2-hydroxy-2-methyl-1-propan-1-one and bis(cyclopentadienyl)
- the heat polymerization initiator of the component (5) is selected from the group consisting of azobisisobutyronitrile, benzoyl peroxide, lauroyl peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, di-t-amyl peroxide, dicumyl peroxide and t-butyl perbenzoate.
- a polymerization reaction proceeds by irradiation with light.
- a polymerization reaction proceeds by heating.
- the crosslinking agent of the component (6) is selected from the group consisting of N,N'-methylenebis-acrylamide, ethylene glycol dimethacrylate, polyethylene glycol 400 diacrylate, diethylene glycol diacrylate, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, neopentylglycol diacrylate, neopentyl glycol diacryl hydroxypivalate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate and trimethylolpropane trimethacrylate.
- the content of each component may be adjusted to form an appropriate gel composition, for example, as follows.
- the first solution contains an acrylic acid monomer as the unsaturated compound, pyrrolidonecarboxylic acid as the acid giving a moisturizer, N,N'-methylenebis-acryletalamide as the crosslinking agent and benzyldimethyl-ketal as the photopolymerization initiator
- their contents are preferably adjusted to amounts of from 20 to 50% by weight, from 1 to 43% by weight, from 0.01 to 1% by weight and from 0.01 to 1% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution
- the second solution contains water and NaOH in amounts of from 7 to 25% by weight and from 0.2 to 13% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, together with KOH in such an amount as to adjust the pH value of the mixture to 4.0 to 8.0.
- the first solution contains an acrylic acid monomer as the unsaturated compound, lactic acid as the acid giving a moisturizer, N,N'-methylenebisacryletalamide as the crosslinking agent and benzyldimethylketal as the photopolymerization initiator
- their contents are preferably adjusted to amounts of from 20 to 50% by weight, from 1 to 32% by weight, from 0.01 to 1% by weight and from 0.01 to 1% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution
- the second solution contains water and NaOH in amounts of from 10 to 25% by weight and from 0.3 to 32% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, together with KOH in such an amount as to adjust the pH value of the mixture to 4.0 to 8.0.
- the first solution contains an acrylic acid monomer as the unsaturated compound, pyrrolidonecarboxylic acid as the acid giving a moisturizer, N,N'-methylenebis-acryletalamide as the crosslinking agent and benzyldimethyl-ketal as the photopolymerization initiator
- their contents are preferably adjusted to in amounts of from 20 to 50% by weight, from 1 to 43% by weight, from 0.01 to 1% by weight and from 0.01 to 1% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution
- the second solution contains water in an amount of from 8 to 25% by weight based on the weight of the mixture of the first solution with the second solution and KOH in such an amount as to adjust the pH value of the mixture to 4.0 to 8.0.
- the first solution contains an acrylic acid monomer as the unsaturated compound, lactic acid as the acid giving a moisturizer, N,N'-methylenebisacryletalamide as the crosslinking agent and benzyldimethylketal as the photopolymerization initiator
- their contents are preferably adjusted to amounts of from 20 to 50% by weight, from 1 to 35% by weight, from 0.01 to 1% by weight and from 0.01 to 1% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution
- the second solution contains water in an amount of from 6 to 25% by weight based on the weight of the mixture of the first solution with the second solution and KOH in such an amount as to adjust the pH value of the mixture to 4.0 to 8.0.
- benzyldimethyl-ketal employed as the photopolymerization initiator and N,N'-methylenebisacrylamide employed as the crosslinking agent are contained in the solution which contained acrylic acid as the radical-polymerizable unsaturated compound and pyrrolidonecarboxylic acid or lactic acid as the acid serving as the moisturizer.
- a polymerization initiator or crosslinking agent may be contained in the solution containing water, KOH and/or NaOH to thereby achieve similar effects.
- the first solution is mixed with the second solution under stirring under the conditions that a temperature ranges from the solidifying point of the solution to 30° C. and a pH value ranges from 4.0 to 8.0, for the period sufficient to make the mixture homogeneous.
- polymerization is carried out by irradiation with an ultraviolet light using a UV irradiator such as a high pressure mercury lamp (output: 750 W, irradiation distance 180 mm) for a period to achieve crosslinking polymerization sufficiently.
- a UV irradiator such as a high pressure mercury lamp (output: 750 W, irradiation distance 180 mm)
- the UV irradiation may be carried out in a nitrogen atmosphere.
- polymerization is carried out by heating at a constant temperature in a thermal reactor for a period to achieve crosslinking polymerization sufficiently.
- the heat polymerization may be carried out in a nitrogen atmosphere.
- the pH value of the first solution is regulated to a low level by the acid employed as the component (2) and thus the spontaneous polymerization of the unsaturated compound employed as the component (1) is suppressed.
- the second solution is free from any component which may possibly change when stored for a long time.
- the acid employed as the component (2) and NaOH or KOH employed as the component (4) together form a moisturizer which also serves as a plasticizer.
- the acid having a high acidity of the component (2) participates in neutralization selectively with NaOH or KOH of the component (4) to thereby prevent the unsaturated compound of the component (1) from becoming unstable due to NaOH or KOH, i.e., the component (4) for a long time.
- the first and second solutions can be each stored for a long time while sustaining its flowability.
- the feedstock solution remains flowable after the preparation, which enables molding of the solid gel conductive composition by casting or injection.
- a reinforcement in the form of a net and the like is impregnated with the feedstock solution which is then subjected to crosslinking polymerization, the high flowability of the feedstock solution facilitates the impregnation and ensures the acquisition of the target gel composition.
- the whole feedstock solution undergoes homogeneous polymerization.
- the crosslinked gel composition suffers from no unevenness in the crosslinking polymerization but has stable qualities.
- this gel composition contains no unpolymerized monomer remaining therein and thus scarcely causes any skin damages.
- the present invention makes it possible to stably produce a conductive composition in the form of a solid gel which contains a moisturizer in an amount required for the performance as the conductive composition.
- solution 1B 5 parts of NaOH and 24 parts of KOH were added to 15 parts of water and homogeneously dissolved therein under stirring.
- the solution thus obtained was referred to as the solution 1B. Since the dissolution of NaOH and KOH was accompanied by the evolution of heat, NaOH and KOH were added gradually so as to prevent the solution from boiling or scattering due to the dissolution heat. After mixing, the solution 1B was sealed in a container and stored.
- the solution 1B was added to the solution 1A while cooling and stirring so as to regulate the solution temperature not to exceed 30° C. and homogeneously dissolved.
- the pyrrolidonecarboxylic acid precipitated in the solution 1A was gradually dissolved and a transparent solution was finally obtained.
- the solution thus obtained was referred to as the solution 1.
- the mixing was accompanied by the heat evolution.
- the solution 1B was added slowly so as to prevent the spontaneous polymerization of the acrylic acid monomer and the boiling or scattering of the solution due to the neutralization heat.
- the solution 1 was sealed in a container and stored in a dark place at 10° C. or below so as to minimize the spontaneous polymerization of the acrylic acid monomer.
- the solution 1 was filled in a silicone mold (width: 50 mm, length: 800 mm, thickness: 1.5 mm) and irradiated by using an ultraviolet light irradiator (a high pressure mercury lamp, output: 750 W, irradiation distance: 180 mm) for 15 seconds to thereby perform crosslinking polymerization.
- an ultraviolet light irradiator a high pressure mercury lamp, output: 750 W, irradiation distance: 180 mm
- solution 2B 7 parts of NaOH and 24 parts of KOH were added to 14 parts of water and homogeneously dissolved therein under stirring.
- the solution thus obtained was referred to as the solution 2B. Since the dissolution of NaOH and KOH was accompanied by the evolution of heat, NaOH and KOH were added gradually so as to prevent the solution from boiling or scattering due to the dissolution heat. After mixing, the solution 2B was sealed in a container and stored.
- the solution 2B was added to the solution 2A while cooling and stirring so as to regulate the solution temperature not to exceed 30° C. and homogeneously dissolved.
- the solution thus obtained was referred to as the solution 2.
- the mixing was accompanied by the heat evolution.
- the solution 2B was added slowly so as to prevent the spontaneous polymerization of the acrylic acid monomer and the boiling or scattering of the solution due to the neutralization heat.
- the solution 2 was sealed in a container and stored in a dark place at 10° C. or below so as to minimize the spontaneous polymerization of the acrylic acid monomer.
- the solution 2 was filled in a silicone mold (width: 50 mm, length: 800 mm, thickness: 1.5 mm) and irradiated by using an ultraviolet light irradiator (a high pressure mercury lamp, output: 750 W, irradiation distance: 180 mm) for 15 seconds to thereby perform crosslinking polymerization.
- an ultraviolet light irradiator a high pressure mercury lamp, output: 750 W, irradiation distance: 180 mm
- the solution thus obtained was referred to as the solution 3B. Since the dissolution of KOH was accompanied by the evolution of heat, KOH were added gradually so as to prevent the solution from boiling or scattering due to the dissolution heat. After mixing, the solution 3B was sealed in a container and stored.
- the solution 3B was added to the solution 3A while cooling and stirring so as to regulate the solution temperature not to exceed 30° C. and homogeneously dissolved.
- the pyrrolidonecarboxylic acid precipitated in the solution 3A was gradually dissolved and a transparent solution was finally obtained.
- the solution thus obtained was referred to as the solution 3.
- the mixing was accompanied by the heat evolution.
- the solution 3B was added slowly so as to prevent the spontaneous polymerization of the acrylic acid monomer and the boiling or scattering of the solution due to the neutralization heat.
- the solution 3 was sealed in a container and stored in a dark place at 10° C. or below so as to minimize the spontaneous polymerization of the acrylic acid monomer.
- the solution 3 was filled in a silicone mold (width: 50 mm, length: 800 mm, thickness: 1.5 mm) and irradiated by using an ultraviolet light irradiator (a high pressure mercury lamp, output: 750 W, irradiation distance: 180 mm) for 15 seconds to thereby perform crosslinking polymerization.
- an ultraviolet light irradiator a high pressure mercury lamp, output: 750 W, irradiation distance: 180 mm
- the solution 4B was added to the solution 4A while cooling and stirring so as to regulate the solution temperature not to exceed 30° C. and homogeneously dissolved.
- the solution thus obtained was referred to as the solution 4.
- the mixing was accompanied by the heat evolution.
- the solution 4B was added slowly so as to prevent the spontaneous polymerization of the acrylic acid monomer and the boiling or scattering of the solution due to the neutralization heat.
- the solution 4 was sealed in a container and stored in a dark place at 10° C. or below so as to minimize the spontaneous polymerization of the acrylic acid monomer.
- the solution 4 was filled in a silicone mold (width: 50 mm, length: 800 mm, thickness: 1.5 mm) and irradiated by using an ultraviolet light irradiator (a high pressure mercury lamp, output: 750 W, irradiation distance: 180 mm) for 15 seconds to thereby perform crosslinking polymerization.
- an ultraviolet light irradiator a high pressure mercury lamp, output: 750 W, irradiation distance: 180 mm
- Table 1 shows the compositions and properties of the conductive compositions of Examples 1 to 4 and Comparative Examples 1 and 2.
- the two-solution type of Examples 1 to 4 each sustained its flowability 7 days or longer after the preparation. After mixing these solutions, the resulting product sustained its flowability for 7 days or longer.
- the one-solution type of Comparative Examples 1 and 2 each lost its flowability 1 minute after the preparation.
- "O" means "yes” and "x” means "no".
- Tables 2 to 8 show the results of trial production of feedstock solutions of the one-solution or two-solution type wherein the contents of the components (% by weight) were varied. Samples of the one-solution type were prepared in the same manner as described in Comparative Example 1 or 2, while samples of the two-solution type were prepared in the same manner as in Examples 1 to 4.
- the evaluation items include "preparability (whether spontaneous polymerization occurs or not)" of each solution and "gelation capacity" of each product thus prepared. O means “yes” while x means “no".
- the first solution contains an acrylic acid monomer, pyrrolidonecarboxylic acid, N,N'-methylenebisacryletalamide and benzyldimethylketal in amounts of from 20 to 50% by weight, from 1 to 43% by weight, from 0.01 to 1% by weight and from 0.01 to 1% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, while the second solution contains water and NaOH in amounts of from 7 to 25% by weight and from 0.2 to 13% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, together with KOH in such an amount as to adjust the pH value of the mixture to 4.0 to 8.0.
- the first solution contains an acrylic acid monomer, lactic acid, N,N'-methylenebisacryletalamide and benzyldimethylketal in amounts of from 20 to 50% by weight, from 1 to 32% by weight, from 0.01 to 1% by weight and from 0.01 to 1% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, while the second solution contains water and NaOH in amounts of from 10 to 25% by weight and from 0.3 to 32% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, together with KOH in such an amount as to adjust the pH value of the mixture to 4.0 to 8.0.
- the first solution contains an acrylic acid monomer, pyrrolidonecarboxylic acid, N,N'-methylenebisacryletalamide and benzyldimethylketal in amounts of from 20 to 50% by weight, from 1 to 43% by weight, from 0.01 to 1% by weight and from 0.01 to 1% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, while the second solution contains water in an amount of from 8 to 25% by weight based on the weight of the mixture of the first solution with the second solution and KOH in such an amount as to adjust the pH value of the mixture to 4.0 to 8.0.
- the first solution contains an acrylic acid monomer, lactic acid, N,N'-methylenebisacryletalamide and benzyldimethylketal in amounts of from 20 to 50% by weight, from 1 to 35% by weight, from 0.01 to 1% by weight and from 0.01 to 1% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, while the second solution contains water in an amount of from 6 to 25% by weight based on the weight of the mixture of the first solution with the second solution and KOH in such an amount as to adjust the pH value of the mixture to 4.0 to 8.0.
- acrylic acid was used as the radical-polymerizable unsaturated compound.
- use can be made as a substitute therefor of other radical-polymerizable unsaturated compounds such as methacrylic acid, crotonic acid, itaconic acid, acrylamide, methacrylamide, 2-acrylamido-2-methylpropanesulfonic acid and polymers of salts thereof, an acrylic acid/vinylpyrrolidone mixture, a vinyl acetate/ethylene mixture and a vinyl acetate/dioctyl maleate mixture to thereby achieve the same effects.
- benzyldimethylketal capable of initiating photopolymerization was employed as the polymerization initiator.
- use can be made as a substitute therefor of 1-hydroxycyclohexyl phenyl ketone, an eutectic mixture of 1-hydroxycyclohexyl phenyl ketone with benzophenone, 2-methyl-1- 4-(methylthio)phenyl!-2-morpholinopropanone-1,2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone-1,2-hydroxy-2-methyl-1-phenyl-propan-1-one, a mixture of 2-hydroxy-2-methyl-1-phenyl-propan-1-one with 2,4,6-trimethylbenzoyldiphenylphosphine oxide, a mixture of 2-hydroxy-2-methyl-1-phenylpropan-1-one with bisacylphosphine oxide, 1- 4-(2-hydroxyethoxy)phenyl!-2-hydroxy-2-methyl-1-propan-1-
- the composition was produced by photopolymerization.
- a polymerization initiator selected from azobisisobutyronitrile, benzoyl peroxide, lauroyl peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, di-t-amyl peroxide, dicumyl peroxide and t-butyl perbenzoate.
- the composition thus produced exhibits effects comparable to those achieved by the one produced by photopolymerization.
- N,N'-methylenebisacrylamide which is a radical-polymerizable, polyfunctional and unsaturated material
- the crosslinking agent was employed in Examples as the crosslinking agent.
- other radical-polymerizable, polyfunctional and unsaturated materials include ethylene glycol dimethacrylate, polyethylene glycol 400 diacrylate, diethylene glycol diacrylate, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, neopentylglycol diacrylate, neopentyl glycol diacryl hydroxypivalate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate and trimethylolpropane trimethacrylate to thereby achieve the same effects.
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Abstract
A process for producing a conductive composition for a biological electrode wherein casting or injection is preformed while maintaining the flowability of the feedstock solution to thereby enable the molding of the solid gel into a desired shape. A process for producing a conductive gel composition for a biological electrode having a function of electrically and physically connecting a living body to an electrode element and comprising at least the following components:
(1) a radical-polymerizable unsaturated compound;
(2) an acid reacting with NaOH or KOH to thereby give a reaction product which is a moisturizer serving as a plasticizer and having a function of supplementing and promoting the physiological humidifying function of the horny layer;
(3) water;
(4) NaOH and/or KOH;
(5) a photopolymerization or light polymerization initiator; and
(6) a crosslinking agent.
which comprises preparing a first solution containing at least the components (1) and (2) and a second solution containing at least the components (3) and (4) independently, mixing the first and second solutions and then subjecting the resulting mixture to irradiation with light or heating.
Description
This invention relates to a conductive composition to be located between the skin and an electrode element when a biological electrode is applied to the skin.
A biological electrode consists of an electrode element made of silver, silver/silver chloride, carbon and the like and a conductive composition connecting the electrode element to the skin and is applied to the surface of a living body in order to output some bioelectrical phenomena (e.g., electrocardiogram, electromyogram, etc.) or electrically stimulate the living body.
Normal human skin has an external layer called "horny layer" which protects the living body against the invasion of various foreign factors. When the skin is contacted with the dry atmosphere, the moisture is lost from the horny layer. Also, the moisture content in the horny layer is reduced as aging proceeds. In such cases, the electrical resistance of the horny layer is elevated. The surface of the skin is not smooth but uneven and has a complicated shape, for example, being curved.
When an electrode element is contacted directly with the skin surface containing less moisture in the horny layer, it is frequently observed that the contact of the electrode element to the skin is inhibited and thus the effective contact area is reduced. As a result, the contact resistance is elevated. In addition, the resistance of the horny layer per se has been elevated as described above. Thus the total electrical resistance is considerably elevated, which causes some troubles, for example, the bioelectrical signal thus output picks up noise, only an unstable record can be obtained, or no record can be obtained in some cases. When the surface of a living body is electrically stimulated via an electrode, the high resistance at the contact area brings about an increase in the current density and thus causes damages such as burn to the living body.
To solve these problems, conductive compositions in the form of liquid, jelly or gel are generally employed in biological electrodes so as to reduce the skin resistance between the living body and the electrode element. These conductive compositions contain a large amount of water and/or electrolytes such as NaCl or KCl which are externally absorbed by the skin horny layer to thereby reduce the skin resistance. Owing to the characteristics of the components, however, such a conductive composition per se has a low viscosity and a high flowability, which makes it difficult to stably sustain the conductive composition between the electrode element and the skin for a prolonged period of time. Thus the electrode element should be provided with a containment space or a holding means such as sponge for supporting the conductive composition. The electrode element should be further provided with an adhesive tape for fixing it on the skin surface. When an adhesive tape is used, however, repeated application and removal of the electrode element cause mechanical damage to the skin.
When an electrode element is applied to the skin surface for a long time via such a conductive composition in an ICU, Holter's electrocardiography, etc., the conductive composition bears mechanical load due to body motion and external pressure. The conductive composition leaks from the electrode element to cause detachment of the electrode element or unstable contact of the electrode element with the skin, thus making it impossible to record the biological signals.
In addition, such a conductive composition is dried during application due to the evaporation of the moisture contained therein. Thus the skin resistance is elevated, thereby making the record of the biological signals unstable. Furthermore, the evaporation of the moisture contained in the conductive composition causes an increase in the chlorine ion concentration in the conductive composition, which induces skin irritation. After the removal of the electrode element, furthermore, such a conductive composition remains on the skin and causes rash.
There are electrode elements usable repeatedly and so-called disposable ones which are thrown away after being used once. In the former ones, a conductive composition is applied to the skin immediately before use. In the latter ones, on the other hand, a conductive composition has been preliminarily filled or incorporated into the electrode in many cases so that they can be easily applied. In the latter case, therefore, it is required to have a structure that the conductive composition is kept not dried until it is used and to store the conductive composition in an airtight package to thereby prevent it from drying during storage. Accordingly, an electrode element of the latter type should have a complicated structure as a whole with taking the use and storage thereof into consideration.
To produce the above-mentioned conductive composition, a feedstock solution is first prepared and poured into a mold followed by UV irradiation or heating for initiating crosslinking polymerization. However, it is observed in some cases that the acrylic acid monomer undergoes spontaneous polymerization immediately after the feedstock solution is prepared owing to a moisturizer contained in the feedstock solution. This is because the moisturizer has a function of reducing the pH value at which spontaneous polymerization of the acrylic acid monomer is initiated and further the acrylic acid becomes unstable, although the acrylic acid monomer generally undergoes spontaneous polymerization due to unstable double bonds when the pH value is high.
When the moisturizer is added at the higher ratio, then the above-mentioned phenomenon occurs at the higher frequency. When the spontaneous polymerization arises, the feedstock solution becomes more viscous and less flowable and gelation occurs before the initiation of the crosslinking polymerization. As a result, the feedstock solution can be hardly poured into a mold and thus short shot of the feedstock solution makes it impossible to mold the solid gel by casting or injection.
Today, biological electrodes are employed for various purposes including electrodiography, electroencephalography, electromyography, stimulation, etc. and, therefore, they are processed into various, complicated forms depending on the purposes. When the solid gel molding by casting or injection becomes impossible, these requirements cannot be satisfied.
On the other hand, it is sometimes effected to impregnate a network reinforcement with a solid gel feedstock solution followed by crosslinking polymerization. When the flowability of the feedstock solution is lowered due to spontaneous polymerization, however, the reinforcement is scarcely impregnated with the feedstock solution and thus the desired gel composition cannot be obtained.
When the flowability of the feedstock solution is lowered before the initiation of the crosslinking polymerization, furthermore, the crosslinking polymerization cannot uniformly proceed and there remain partially unpolymerized monomers, thus causing skin irritation. In addition, the occurrence of the spontaneous polymerization makes the feedstock solution chemically unstable and thus shortens its pot life. In such a case, it is difficult to prepare the feedstock solution in a large batch, which brings about a problem that mass production on, for example, an automated line can be hardly performed. In the case of sheet type electrodes which are continuously produced by applying a feedstock solution onto film-type electrode elements, the spontaneous polymerization of the feedstock solution causes an increase in the viscosity of the feedstock solution and makes it chemically unstable. As a result, the gelation proceeds and the application of the feedstock solution becomes difficult.
An object of the present invention is to provide a process for producing a conductive composition wherein casting or injection is performed while maintaining the flowability of the feedstock solution to thereby mold the feedstock solution into a solid gel of a desired shape.
The present invention relates to a process for producing a conductive gel composition for a biological electrode having a function of electrically and physically connecting a living body to an electrode element and comprising the following components:
(1) a radical-polymerizable unsaturated compound;
(2) an acid reacting with NaOH or KOH to thereby give a reaction product which is a moisturizer serving as a plasticizer and having a function of supplementing and promoting the physiological humidifying function of the horny layer;
(3) water;
(4) NaOH and/or KOH;
(5) a photopolymerization or light polymerization initiator; and
(6) a crosslinking agent,
which comprises preparing a first solution containing at least the components (1) and (2) and a second solution containing at least the components (3) and (4) independently, mixing the first and second solutions together and then subjecting the resulting mixture to irradiation with light or heating.
The unsaturated compound of the component (1) contained in the conductive composition of the present invention is selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, itaconic acid, acrylamide, methacrylamide, 2-acrylamido-2-methylpropane-sulfonic acid and salts thereof, and mixtures thereof, an acrylic acid/vinylpyrrolidone mixture, a vinyl acetate/ethylene mixture and a vinyl acetate/dioctyl maleate mixture.
These unsaturated compounds make it possible to easily perform the polymerization.
The acid employed as the component (2), which reacts with NaOH or KOH to give a moisturizer, is lactic acid, pyrrolidonecarboxylic acid or a combination thereof.
Because of being ionic, such a moisturizer can elevate the conductivity of the conductive composition per se without adding any electrolyte (NaCl, KCl, etc.), different from the conventional cases wherein nonionic polyhydric alcohols are added as a plasticizer.
When the moisturizer penetrates into the skin horny layer, the water contained in the tissue binds to the moisturizer to thereby improve the humidifying properties of the horny layer per se. Thus the moisture content in the skin horny layer can be elevated. An increase in the moisture content in the skin horny layer results in a decrease in the electrical resistance of the horny layer and, in its turn, reduces the impedance of the electrode against the skin.
Since the moisturizer contributes to the reduction of the impedance to the skin, the moisture content in the conductive composition can be regulated to a low level and thus the stickiness thereof can be improved. As a result, the evaporation of the moisture from the composition can be suppressed during storage or application.
It is also possible to avoid the problem of the loss in stickiness due to the oozing of water from the conductive composition. Moreover, the conductive composition is free from any skin troubles caused by the percutaneous absorption of the excessive water or electrolytes, etc.
Since such a moisturizer is contained in the horny layer inherently, the addition thereof scarcely causes any skin irritation.
The moisturizer (pyrrolidonecarboxylic acid, lactic acid, etc.) also has an effect of imparting stickiness. Thus the stickiness of the composition to the skin can be further strengthened by adding it. In addition, the stickiness of the composition to the skin can be arbitrarily controlled easily by varying its content. That is to say, the moisturizer has four functions (i.e., as a plasticizer, as an electrolyte, as an agent for increasing the moisture content in the horny layer and as a an agent of imparting stickiness). Thus it is the most desirable material as a component of a conductive composition for a biological electrode.
The photopolymerization initiator of the component (5) is selected from the group consisting of benzildimethyl-ketal, 1-hydroxycyclohexyl phenyl ketone, an eutectic mixture of 1-hydroxycyclohexyl phenyl ketone with benzophenone, 2-methyl-1- 4-(methylthio)phenyl!-2-morpholino-propanone-1, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-hydroxy-2-methyl-1-phenylpropan-1-one, a mixture of 2-hydroxy-2-methyl-1-phenylpropan-1-one with 2,4,6-trimethylbenzoyldiphenylphosphine oxide, a mixture of 2-hydroxy-2-methyl-1-phenylpropan-1-one with bisacylphosphine oxide, 1- 4-(2-hydroxyethoxy)phenyl!-2-hydroxy-2-methyl-1-propan-1-one and bis(cyclopentadienyl)-bis(2,6-difluoro-3-(pyr-1-yl)titanium.
The heat polymerization initiator of the component (5) is selected from the group consisting of azobisisobutyronitrile, benzoyl peroxide, lauroyl peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, di-t-amyl peroxide, dicumyl peroxide and t-butyl perbenzoate.
When the photopolymerization initiator is used, a polymerization reaction proceeds by irradiation with light. When the heat polymerization initiator is used, a polymerization reaction proceeds by heating.
The crosslinking agent of the component (6) is selected from the group consisting of N,N'-methylenebis-acrylamide, ethylene glycol dimethacrylate, polyethylene glycol 400 diacrylate, diethylene glycol diacrylate, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, neopentylglycol diacrylate, neopentyl glycol diacryl hydroxypivalate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate and trimethylolpropane trimethacrylate.
The content of each component may be adjusted to form an appropriate gel composition, for example, as follows.
When the first solution contains an acrylic acid monomer as the unsaturated compound, pyrrolidonecarboxylic acid as the acid giving a moisturizer, N,N'-methylenebis-acryletalamide as the crosslinking agent and benzyldimethyl-ketal as the photopolymerization initiator, their contents are preferably adjusted to amounts of from 20 to 50% by weight, from 1 to 43% by weight, from 0.01 to 1% by weight and from 0.01 to 1% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, while the second solution contains water and NaOH in amounts of from 7 to 25% by weight and from 0.2 to 13% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, together with KOH in such an amount as to adjust the pH value of the mixture to 4.0 to 8.0.
When the first solution contains an acrylic acid monomer as the unsaturated compound, lactic acid as the acid giving a moisturizer, N,N'-methylenebisacryletalamide as the crosslinking agent and benzyldimethylketal as the photopolymerization initiator, their contents are preferably adjusted to amounts of from 20 to 50% by weight, from 1 to 32% by weight, from 0.01 to 1% by weight and from 0.01 to 1% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, while the second solution contains water and NaOH in amounts of from 10 to 25% by weight and from 0.3 to 32% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, together with KOH in such an amount as to adjust the pH value of the mixture to 4.0 to 8.0.
When the first solution contains an acrylic acid monomer as the unsaturated compound, pyrrolidonecarboxylic acid as the acid giving a moisturizer, N,N'-methylenebis-acryletalamide as the crosslinking agent and benzyldimethyl-ketal as the photopolymerization initiator, their contents are preferably adjusted to in amounts of from 20 to 50% by weight, from 1 to 43% by weight, from 0.01 to 1% by weight and from 0.01 to 1% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, while the second solution contains water in an amount of from 8 to 25% by weight based on the weight of the mixture of the first solution with the second solution and KOH in such an amount as to adjust the pH value of the mixture to 4.0 to 8.0.
When the first solution contains an acrylic acid monomer as the unsaturated compound, lactic acid as the acid giving a moisturizer, N,N'-methylenebisacryletalamide as the crosslinking agent and benzyldimethylketal as the photopolymerization initiator, their contents are preferably adjusted to amounts of from 20 to 50% by weight, from 1 to 35% by weight, from 0.01 to 1% by weight and from 0.01 to 1% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, while the second solution contains water in an amount of from 6 to 25% by weight based on the weight of the mixture of the first solution with the second solution and KOH in such an amount as to adjust the pH value of the mixture to 4.0 to 8.0.
In each of the above compositions, benzyldimethyl-ketal employed as the photopolymerization initiator and N,N'-methylenebisacrylamide employed as the crosslinking agent are contained in the solution which contained acrylic acid as the radical-polymerizable unsaturated compound and pyrrolidonecarboxylic acid or lactic acid as the acid serving as the moisturizer. Alternatively, such a polymerization initiator or crosslinking agent may be contained in the solution containing water, KOH and/or NaOH to thereby achieve similar effects.
The first solution is mixed with the second solution under stirring under the conditions that a temperature ranges from the solidifying point of the solution to 30° C. and a pH value ranges from 4.0 to 8.0, for the period sufficient to make the mixture homogeneous.
When the photopolymerization initiator is used, polymerization is carried out by irradiation with an ultraviolet light using a UV irradiator such as a high pressure mercury lamp (output: 750 W, irradiation distance 180 mm) for a period to achieve crosslinking polymerization sufficiently. The UV irradiation may be carried out in a nitrogen atmosphere.
When the heat polymerization initiator is used, polymerization is carried out by heating at a constant temperature in a thermal reactor for a period to achieve crosslinking polymerization sufficiently. The heat polymerization may be carried out in a nitrogen atmosphere.
In the process for producing a conductive composition in accordance with the present invention, the pH value of the first solution is regulated to a low level by the acid employed as the component (2) and thus the spontaneous polymerization of the unsaturated compound employed as the component (1) is suppressed. The second solution is free from any component which may possibly change when stored for a long time. When the first solution is mixed with the second solution and the resulting mixture is subjected to a polymerization reaction by irradiation with light or heating, then the unsaturated compound employed as the component (1) undergoes crosslinking polymerization. Further, the acid employed as the component (2) and NaOH or KOH employed as the component (4) together form a moisturizer which also serves as a plasticizer. Furthermore, the acid having a high acidity of the component (2) participates in neutralization selectively with NaOH or KOH of the component (4) to thereby prevent the unsaturated compound of the component (1) from becoming unstable due to NaOH or KOH, i.e., the component (4) for a long time.
Thus, the first and second solutions can be each stored for a long time while sustaining its flowability.
As described above, the feedstock solution remains flowable after the preparation, which enables molding of the solid gel conductive composition by casting or injection. When a reinforcement in the form of a net and the like is impregnated with the feedstock solution which is then subjected to crosslinking polymerization, the high flowability of the feedstock solution facilitates the impregnation and ensures the acquisition of the target gel composition.
In addition, the whole feedstock solution undergoes homogeneous polymerization. Thus the crosslinked gel composition suffers from no unevenness in the crosslinking polymerization but has stable qualities. Furthermore, this gel composition contains no unpolymerized monomer remaining therein and thus scarcely causes any skin damages.
It is also possible to continuously manufacture sheet electrodes by applying the feedstock solution to film electrodes.
As described above, the present invention makes it possible to stably produce a conductive composition in the form of a solid gel which contains a moisturizer in an amount required for the performance as the conductive composition.
The following examples illustrate the present invention in more detail, but are not to be construed to limit the scope of the invention. In the examples, the term "part" means "part by weight" unless otherwise indicates.
To 38 parts of acrylic acid monomer were added 0.19 parts of N,N'-methylenebisacrylamide and 0.19 parts of benzyldimethylketal and homogeneously dissolved under stirring. These components may be added at an arbitrary order. Next, 17 parts of pyrrolidonecarboxylic acid was added thereto. Although the pyrrolidonecarboxylic acid was precipitated, no problem was caused thereby. The solution thus obtained was referred to as the solution 1A.
Since the above-mentioned procedure was accompanied by the evolution of little reaction heat, no particular operation for cooling, etc. was required therefor. After mixing, the obtained solution was sealed in a container and stored in a dark place at 10° C. or below so as to minimize the spontaneous polymerization of the acrylic acid monomer.
Next, 5 parts of NaOH and 24 parts of KOH were added to 15 parts of water and homogeneously dissolved therein under stirring. The solution thus obtained was referred to as the solution 1B. Since the dissolution of NaOH and KOH was accompanied by the evolution of heat, NaOH and KOH were added gradually so as to prevent the solution from boiling or scattering due to the dissolution heat. After mixing, the solution 1B was sealed in a container and stored.
Then the solution 1B was added to the solution 1A while cooling and stirring so as to regulate the solution temperature not to exceed 30° C. and homogeneously dissolved. In the process of the addition, the pyrrolidonecarboxylic acid precipitated in the solution 1A was gradually dissolved and a transparent solution was finally obtained. The solution thus obtained was referred to as the solution 1. In this step, the mixing was accompanied by the heat evolution. Thus the solution 1B was added slowly so as to prevent the spontaneous polymerization of the acrylic acid monomer and the boiling or scattering of the solution due to the neutralization heat.
After mixing, the solution 1 was sealed in a container and stored in a dark place at 10° C. or below so as to minimize the spontaneous polymerization of the acrylic acid monomer.
Subsequently, the solution 1 was filled in a silicone mold (width: 50 mm, length: 800 mm, thickness: 1.5 mm) and irradiated by using an ultraviolet light irradiator (a high pressure mercury lamp, output: 750 W, irradiation distance: 180 mm) for 15 seconds to thereby perform crosslinking polymerization. Thus a transparent and sticky conductive composition in the form of a solid gel sheet was obtained.
To 38 parts of acrylic acid monomer were added 0.19 parts of N,N'-methylenebisacrylamide, 0.19 parts of benzyldimethylketal and 16 parts of lactic acid and homogeneously dissolved under stirring. The solution thus obtained was referred to as the solution 2A. These components may be added at an arbitrary order.
Since the above-mentioned procedure was accompanied by the evolution of little reaction heat, no particular operation for cooling, etc. was required therefor. After mixing, the resulting solution was sealed in a container and stored in a dark place at 10° C. or below so as to minimize the spontaneous polymerization of the acrylic acid monomer.
Next, 7 parts of NaOH and 24 parts of KOH were added to 14 parts of water and homogeneously dissolved therein under stirring. The solution thus obtained was referred to as the solution 2B. Since the dissolution of NaOH and KOH was accompanied by the evolution of heat, NaOH and KOH were added gradually so as to prevent the solution from boiling or scattering due to the dissolution heat. After mixing, the solution 2B was sealed in a container and stored.
Then the solution 2B was added to the solution 2A while cooling and stirring so as to regulate the solution temperature not to exceed 30° C. and homogeneously dissolved. The solution thus obtained was referred to as the solution 2. In this step, the mixing was accompanied by the heat evolution. Thus the solution 2B was added slowly so as to prevent the spontaneous polymerization of the acrylic acid monomer and the boiling or scattering of the solution due to the neutralization heat.
After mixing, the solution 2 was sealed in a container and stored in a dark place at 10° C. or below so as to minimize the spontaneous polymerization of the acrylic acid monomer.
Subsequently, the solution 2 was filled in a silicone mold (width: 50 mm, length: 800 mm, thickness: 1.5 mm) and irradiated by using an ultraviolet light irradiator (a high pressure mercury lamp, output: 750 W, irradiation distance: 180 mm) for 15 seconds to thereby perform crosslinking polymerization. Thus a transparent and sticky conductive composition in the form of a solid gel sheet was obtained.
To 31 parts of acrylic acid monomer were added 0.16 parts of N,N'-methylenebisacrylamide and 0.16 parts of benzyldimethylketal and homogeneously dissolved under stirring. These components may be added at an arbitrary order. Next, 26 parts of pyrrolidonecarboxylic acid was added thereto. Although the pyrrolidonecarboxylic acid was precipitated, no problem was caused thereby. The solution thus obtained was referred to as the solution 3A.
Since the above-mentioned procedure was accompanied by the evolution of little reaction heat, no particular operation for cooling, etc. was required therefor. After mixing, the resulting solution was sealed in a container and stored in a dark place at 10° C. or below so as to minimize the spontaneous polymerization of the acrylic acid monomer.
Next, 31 parts of KOH was added to 13 parts of water and homogeneously dissolved therein under stirring. The solution thus obtained was referred to as the solution 3B. Since the dissolution of KOH was accompanied by the evolution of heat, KOH were added gradually so as to prevent the solution from boiling or scattering due to the dissolution heat. After mixing, the solution 3B was sealed in a container and stored.
Then the solution 3B was added to the solution 3A while cooling and stirring so as to regulate the solution temperature not to exceed 30° C. and homogeneously dissolved. In the process of the addition, the pyrrolidonecarboxylic acid precipitated in the solution 3A was gradually dissolved and a transparent solution was finally obtained. The solution thus obtained was referred to as the solution 3. In this step, the mixing was accompanied by the heat evolution. Thus the solution 3B was added slowly so as to prevent the spontaneous polymerization of the acrylic acid monomer and the boiling or scattering of the solution due to the neutralization heat.
After mixing, the solution 3 was sealed in a container and stored in a dark place at 10° C. or below so as to minimize the spontaneous polymerization of the acrylic acid monomer.
Subsequently, the solution 3 was filled in a silicone mold (width: 50 mm, length: 800 mm, thickness: 1.5 mm) and irradiated by using an ultraviolet light irradiator (a high pressure mercury lamp, output: 750 W, irradiation distance: 180 mm) for 15 seconds to thereby perform crosslinking polymerization. Thus a transparent and sticky conductive composition in the form of a solid gel sheet was obtained.
To 28 parts of acrylic acid monomer were added 0.13 parts of N,N'-methylenebisacrylamide, 0.13 parts of benzyldimethylketal and 24 parts of lactic acid and homogeneously dissolved under stirring. The solution thus obtained was referred to as the solution 4A. These components may be added at an arbitrary order.
Since the above-mentioned procedure was accompanied by the evolution of little reaction heat, no particular operation for cooling, etc. was required therefor. After mixing, the resulting solution was sealed in a container and stored in a dark place at 10° C. or below so as to minimize the spontaneous polymerization of the acrylic acid monomer.
Next, 33 parts of KOH was added to 15 parts of water and homogeneously dissolved therein under stirring. The solution thus obtained was referred to as the solution 4B. Since the dissolution of KOH was accompanied by the evolution of heat, KOH was added gradually so as to prevent the solution from boiling or scattering due to the dissolution heat. After mixing, the solution 4B was sealed in a container and stored.
Then the solution 4B was added to the solution 4A while cooling and stirring so as to regulate the solution temperature not to exceed 30° C. and homogeneously dissolved. The solution thus obtained was referred to as the solution 4. In this step, the mixing was accompanied by the heat evolution. Thus the solution 4B was added slowly so as to prevent the spontaneous polymerization of the acrylic acid monomer and the boiling or scattering of the solution due to the neutralization heat.
After mixing, the solution 4 was sealed in a container and stored in a dark place at 10° C. or below so as to minimize the spontaneous polymerization of the acrylic acid monomer.
Subsequently, the solution 4 was filled in a silicone mold (width: 50 mm, length: 800 mm, thickness: 1.5 mm) and irradiated by using an ultraviolet light irradiator (a high pressure mercury lamp, output: 750 W, irradiation distance: 180 mm) for 15 seconds to thereby perform crosslinking polymerization. Thus a transparent and sticky conductive composition in the form of a solid gel sheet was obtained.
To 22 parts of acrylic acid monomer were added 0.09 parts of N,N'-methylenebisacrylamide, 0.09 parts of benzyldimethylketal, 13 parts of water, 50 parts of pyrrolidonecarboxylic acid and 13 parts of KOH in this order while homogeneously stirring and cooling so as to regulate the solution temperature not to exceed 30° C.
One minute after mixing, the solution set to gel just like sherbet or corn snow and did not flow even though the container was tilted. Thus, casting or injection of the product into an electrode mold was impossible in practice.
To 22 parts of acrylic acid monomer were added 0.09 parts of N,N'-methylenebisacrylamide, 0.09 parts of benzyldimethylketal, 13 parts of water, 50 parts of potassium lactate and 13 parts of KOH in this order while homogeneously stirring and cooling so as to regulate the solution temperature not to exceed 30° C.
One minute after mixing, the solution set to gel just like sherbet or corn snow and did not flow even though the container was tilted. Thus, casting or injection of the product into an electrode mold was impossible in practice.
Table 1 shows the compositions and properties of the conductive compositions of Examples 1 to 4 and Comparative Examples 1 and 2. As the evaluation data indicate, the two-solution type of Examples 1 to 4 each sustained its flowability 7 days or longer after the preparation. After mixing these solutions, the resulting product sustained its flowability for 7 days or longer. In contrast, the one-solution type of Comparative Examples 1 and 2 each lost its flowability 1 minute after the preparation. In Table 1, "O" means "yes" and "x" means "no".
TABLE 1 __________________________________________________________________________ Composition (wt. %) Comp. Ex. 1 Comp. Ex. 2 Ex. 1 Ex. 2 Ex. 3 Ex. 4 (Type) 1-soln. 1-soln. 2-soln. 2-soln. 2-soln. 2-soln. __________________________________________________________________________ N,N'-methy1enebisacrylamide 0.09 0.09 0.19 0.19 0.16 0.13 benzyldimethylketal 0.09 0.09 0.19 0.19 0.16 0.13 acrylic acid monomer 22 22 38 38 31 28 NaOH -- -- 5 -- _ -- KOH 13 13 24 24 31 33 water 13 13 15 14 13 15 potassium PCA 50 -- -- -- -- -- potassium lactate -- 50 -- -- -- -- PCA -- -- 17 -- 26 -- lactic acid -- -- -- 16 -- 24 Evaluation: change in flowability (time required for losing flowability) 1 soln.-type (min) 1 1 -- -- -- -- 2 soln.-type A (days) -- -- >7 >7 >7 >7 B (days) -- -- >7 >7 >7 >7 gelation capacity x x ◯ ◯ ◯ ◯ pot life (days) x x >7 >7 >7 >7 __________________________________________________________________________
Tables 2 to 8 show the results of trial production of feedstock solutions of the one-solution or two-solution type wherein the contents of the components (% by weight) were varied. Samples of the one-solution type were prepared in the same manner as described in Comparative Example 1 or 2, while samples of the two-solution type were prepared in the same manner as in Examples 1 to 4. The evaluation items include "preparability (whether spontaneous polymerization occurs or not)" of each solution and "gelation capacity" of each product thus prepared. O means "yes" while x means "no".
TABLE 2 __________________________________________________________________________ Composition (wt. %) S1 S2 S3 S4 S5 56 57 58 moisturizer (%) 1 1 1 1 1 1 1 1 (Type) 1-soln. 1-soln. 1-soln. 1-soln. 2-soln. 2-soln. 2-soln 2-soln. __________________________________________________________________________ N,N'-methylenebisacrylamide 0.23 0.23 0.23 0.23 0.23 0.23 0.23 0.23 benzyldimethylketal 0.23 0.23 0.23 0.23 0.23 0.23 0.23 0.23 acrylic acid monomer 47 47 47 47 47 47 47 47 NaOH -- -- -- -- 0.3 0.4 -- -- KOH 30 30 30 -- 30 30 31 30 water 22 22 22 22 21 21 21 21 sodium PCA 1 -- -- -- -- -- -- -- sodium lactate -- 1 -- -- -- -- -- -- potassium.PCA -- -- 1 -- -- -- -- -- potassium lactate -- -- -- 1 -- -- -- -- PCA -- -- -- -- 0.85 -- 0.77 -- lactic acid -- -- -- -- -- 0.80 -- 0.70 Evaluation: preparability ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ gelation capacity ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ __________________________________________________________________________
TABLE 3 __________________________________________________________________________ Composition (wt. %) S9 S10 S11 S12 S13 S14 S15 S16 moisturizer (%) 5 5 5 5 5 5 5 5 (Type) 1-soln. 1 soln. 1-soln. 1-soln. 2-soln. 2-soln. 2-soln. 2-soln. __________________________________________________________________________ N,N'-methylenebisacrylamide 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 benzyldimethylketal 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 acrylic acid monomer 45 45 45 45 45 45 45 45 NaOH -- -- -- -- 1 2 -- -- KOH 29 29 29 29 29 29 30 31 water 21 21 21 21 20 20 20 20 sodium PCA 5 -- -- -- -- -- -- -- sodium lactate -- 5 -- -- -- -- -- -- potassium PCA -- -- 5 -- -- -- -- -- potassium lactate -- -- -- 5 -- -- -- -- PCA -- -- -- -- 4.3 -- 3.9 -- lactic acid -- -- -- -- -- 4.0 -- 3.5 Evaluation: preparability ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ gelation capacity ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ __________________________________________________________________________
TABLE 4 __________________________________________________________________________ Composition (wt. %) S17 S18 S19 S20 S21 S22 S23 S24 moisturizer (%) 10 10 10 10 10 10 10 10 (Type) 1-soln. 1-soln, 1-soln. 2-soln. 2-soln. 2-soln. 2-soln. 2-soln. __________________________________________________________________________ N,N'-methylenebisacrylaxnide 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 benzyldiinethylketal 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 acrylic acid monomer 43 43 43 43 43 43 43 43 NaOH -- -- -- -- 3 4 -- -- KOH 27 27 27 27 27 27 31 32 water 20 20 20 20 18 18 19 18 sodium PCA 10 -- -- -- -- -- -- -- sodium lactate -- 10 -- -- -- -- -- -- potassiwn PCA -- -- 10 -- -- -- -- -- potassium lactate -- -- -- 10 -- -- -- -- PCA -- -- -- -- 8.5 -- 7.7 -- lactic acid -- -- -- -- -- 8.0 -- 7.0 Evaluation: preparability ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ qelation capacity ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ __________________________________________________________________________
TABLE 5 __________________________________________________________________________ Composition (wt. %) S25 S26 S27 S28 S29 S30 S31 S32 moisturizer (%) 20 20 20 20 20 20 20 20 (Type) 1-soln. 1-soln. 1-soln. 1-soln. 1-soln. 1-soln. 1 soln. 1-soln. __________________________________________________________________________ N,N'-methylenebisacrylamide 0.19 0.19 0.19 0.19 0.19 0.19 0.19 0.19 benzyldimethylketal 0.19 0.19 0.19 0.19 0.19 0.19 0.19 0.19 acrylic acid monomer 38 38 38 38 38 38 38 38 NaQH -- -- -- -- 5 7 -- -- KOH 24 24 24 24 24 24 31 33 water 17 17 17 17 15 14 15 15 sodium PCA 20 -- -- -- -- -- -- -- sodium lactate -- 20 -- -- -- -- -- -- potassium PCA -- -- 20 -- -- -- -- -- potassium lactate -- -- -- 20 -- -- -- -- PCA -- -- -- -- 17 -- 15 -- lactic acid -- -- -- -- -- 16 -- 14 Evaluation: preparability x x ◯ ◯ ◯ ◯ ◯ ◯ gelation capacity x x ◯ ◯ ◯ ◯ ◯ ◯ __________________________________________________________________________
TABLE 6 __________________________________________________________________________ Composition (wt. %) S33 S34 S35 S36 S37 S38 S39 S40 moisturizer (%) 40 40 40 40 40 40 40 40 (Type) 1-soln. 1-soln. 1-soln. 1-soln. 2-soln. 2-soln. 2-soln. 2-soln. __________________________________________________________________________ N,N'-methylenebisacrylainide 0.14 0.14 0.14 0.14 0.14 0.14 0.14 0.14 benzyldimethylketal 0.14 0.14 0.14 0.14 0.14 0.14 0.14 0.14. acrylic acid monomer 29 29 29 29 29 29 29 . 29 NaOH -- -- -- -- 11 14 -- -- KOH 18 18 18 18 18 18 32 36 water 13 13 13 13 8 7 9 7 sodium PCA 40 -- -- -- -- -- -- -- sodium lactate -- 40 -- -- -- -- -- -- potassium PCA -- -- 40 -- -- -- -- -- potassiwn lactate -- -- -- 40 -- -- -- -- PCA -- -- -- -- 34 -- 31 -- lactic acid -- -- -- -- -- 32 -- 28 Evaluation: preparability x x x x ◯ ◯ ◯ ◯ gelation capacity x x x x ◯ ◯ ◯ ◯ __________________________________________________________________________
TABLE 7 __________________________________________________________________________ Composition (wt. %) S41 S42 S43 S44 S45 S46 S47 S48 moisturizer (%) 50 40 50 50 60 50 60 60 (Type) 2-soln. 2-soln. 2-soln. 2-soln. 2-soln. 2-soln. 2-soln. 2-soln. __________________________________________________________________________ N,N'-methylenebisacrylainide 0.09 0.11 0.09 0.09 0.08 0.09 0.08 0.08 benzyldimethylketal 0.09 0.11 0.09 0.09 0.08 0.09 0.08 0.08 acrylic acid monomer 22 27 22 22 18 22 18 18 NaOH 13 14 -- -- 16 18 -- -- KOH 12 16 30 35 11 13 31 37 water 7 10 8 6 4 5 4 2 sodium PCA -- -- -- -- -- -- -- -- sodium lactate -- -- -- -- -- -- -- -- potassium PCA -- -- -- -- -- -- -- -- potassium lactate -- -- -- -- -- -- -- -- PCA 43 -- 39 -- 51 -- 46 -- lactic acid -- 32 -- 35 -- 40 -- 42 Evaluation: preparability ◯ ◯ ◯ ◯ x x x x gelation capacity ◯ ◯ ◯ ◯ x x x x __________________________________________________________________________
TABLE 8 __________________________________________________________________________ Composition (wt. %) S49 S50 S51 S52 S53 S54 S55 S56 moisturizer (%) 60 60 60 60 60 60 60 60 (Type) 1-soln. 1-soln. 1-soln. 1-soln. 2-soln. 2-soln. 2-soln. 2-soln. __________________________________________________________________________ N,N'-methylenebisacrylamide 0.09 0.09 0.09. 0.09 0.09 0.09 0.09 0.09 benzyldimethylketal 0.09 0.09 0.09 0.09 0.09 0.09 0.09 0.09 acrylic acid monomer 19 19 19 19 19 19 19 19 NaOH -- -- -- -- 16 21 -- -- KOH 12 12 12 12 12 12 32 38 water 9 9 9 9 2 -1 2 0 sodium PCA 60 -- -- -- -- -- -- -- sodium lactate -- 60 -- -- -- -- -- -- potassium PCA -- -- 60 -- -- -- -- -- potassium lactate -- -- -- 60 -- -- -- -- PCA -- -- -- -- 51 -- 46 -- lactic acid -- -- -- -- -- 48 -- 42 Evaluation preparability x x x x x x x x gelation capacity x x x x x x x x __________________________________________________________________________
These results indicate that when each of the components in the 2 solutions fell into within the range as specified below, the feedstock solution had an appropriate flowability and could be molded into a desired shape by casting, etc.
In the case of using pyrrolidonecarboxylic acid as the acid giving the moisturizer (1), the first solution contains an acrylic acid monomer, pyrrolidonecarboxylic acid, N,N'-methylenebisacryletalamide and benzyldimethylketal in amounts of from 20 to 50% by weight, from 1 to 43% by weight, from 0.01 to 1% by weight and from 0.01 to 1% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, while the second solution contains water and NaOH in amounts of from 7 to 25% by weight and from 0.2 to 13% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, together with KOH in such an amount as to adjust the pH value of the mixture to 4.0 to 8.0.
In the case of using lactic acid as the acid giving the moisturizer (1), the first solution contains an acrylic acid monomer, lactic acid, N,N'-methylenebisacryletalamide and benzyldimethylketal in amounts of from 20 to 50% by weight, from 1 to 32% by weight, from 0.01 to 1% by weight and from 0.01 to 1% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, while the second solution contains water and NaOH in amounts of from 10 to 25% by weight and from 0.3 to 32% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, together with KOH in such an amount as to adjust the pH value of the mixture to 4.0 to 8.0.
In the case of using pyrrolidonecarboxylic acid as the acid giving the moisturizer (2), the first solution contains an acrylic acid monomer, pyrrolidonecarboxylic acid, N,N'-methylenebisacryletalamide and benzyldimethylketal in amounts of from 20 to 50% by weight, from 1 to 43% by weight, from 0.01 to 1% by weight and from 0.01 to 1% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, while the second solution contains water in an amount of from 8 to 25% by weight based on the weight of the mixture of the first solution with the second solution and KOH in such an amount as to adjust the pH value of the mixture to 4.0 to 8.0.
In the case of using lactic acid as the acid giving the moisturizer (2), the first solution contains an acrylic acid monomer, lactic acid, N,N'-methylenebisacryletalamide and benzyldimethylketal in amounts of from 20 to 50% by weight, from 1 to 35% by weight, from 0.01 to 1% by weight and from 0.01 to 1% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, while the second solution contains water in an amount of from 6 to 25% by weight based on the weight of the mixture of the first solution with the second solution and KOH in such an amount as to adjust the pH value of the mixture to 4.0 to 8.0.
Although a single acid was employed as the acid giving the moisturizer in Examples and trial products, the combined use of these acids can achieve the same effects.
In Examples 1 to 4 shown in Table 1 and the trial products S1 to S56 shown in Tables 2 to 8, acrylic acid was used as the radical-polymerizable unsaturated compound. Alternatively, use can be made as a substitute therefor of other radical-polymerizable unsaturated compounds such as methacrylic acid, crotonic acid, itaconic acid, acrylamide, methacrylamide, 2-acrylamido-2-methylpropanesulfonic acid and polymers of salts thereof, an acrylic acid/vinylpyrrolidone mixture, a vinyl acetate/ethylene mixture and a vinyl acetate/dioctyl maleate mixture to thereby achieve the same effects.
Similarly, benzyldimethylketal capable of initiating photopolymerization was employed as the polymerization initiator. Alternatively, use can be made as a substitute therefor of 1-hydroxycyclohexyl phenyl ketone, an eutectic mixture of 1-hydroxycyclohexyl phenyl ketone with benzophenone, 2-methyl-1- 4-(methylthio)phenyl!-2-morpholinopropanone-1,2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone-1,2-hydroxy-2-methyl-1-phenyl-propan-1-one, a mixture of 2-hydroxy-2-methyl-1-phenyl-propan-1-one with 2,4,6-trimethylbenzoyldiphenylphosphine oxide, a mixture of 2-hydroxy-2-methyl-1-phenylpropan-1-one with bisacylphosphine oxide, 1- 4-(2-hydroxyethoxy)phenyl!-2-hydroxy-2-methyl-1-propan-1-one and bis(cyclopentadienyl)-bis(2,6-difluoro-3-(pyr-1-yl)titanium to thereby achieve the same effects.
In each of Examples, the composition was produced by photopolymerization. However, it is also possible to produce the composition by heat polymerization. In such a case, use can be made of a polymerization initiator selected from azobisisobutyronitrile, benzoyl peroxide, lauroyl peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, di-t-amyl peroxide, dicumyl peroxide and t-butyl perbenzoate. The composition thus produced exhibits effects comparable to those achieved by the one produced by photopolymerization.
Similarly, N,N'-methylenebisacrylamide, which is a radical-polymerizable, polyfunctional and unsaturated material, was employed in Examples as the crosslinking agent. Alternatively, usable examples of other radical-polymerizable, polyfunctional and unsaturated materials include ethylene glycol dimethacrylate, polyethylene glycol 400 diacrylate, diethylene glycol diacrylate, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, neopentylglycol diacrylate, neopentyl glycol diacryl hydroxypivalate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate and trimethylolpropane trimethacrylate to thereby achieve the same effects.
While the invention has been described in detail and with reference to specific examples thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.
Claims (10)
1. A process for producing a conductive gel composition for a biological electrode having a function of electrically and physically connecting a living body to an electrode element and comprising the following components:
(1) a radical-polymerizable unsaturated compound;
(2) an acid reacting with NaOH or KOH to thereby give a reaction product which is a moisturizer serving as a plasticizer and having a function of supplementing and promoting the physiological humidifying function of a horny layer;
(3) water;
(4) NaOH and/or KOH;
(5) a photopolymerization or heat polymerization initiator; and
(6) a crosslinking agent; which comprises preparing a first solution containing at least the components (1) and (2) and a second solution containing at least the components (3) and (4) independently, wherein components (5) and (6) are added to either the first or second solution, mixing the first and second solutions together and then subjecting the resulting mixture to irradiation with light or heating.
2. A process for producing a conductive composition for a biological electrode as claimed in claim 1, wherein said unsaturated compound is selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, itaconic acid, acrylamide, methacrylamide, 2-acrylamide-2-methylpropanesulfonic acid and polymers of salts thereof, an acrylic acid/vinylpyrrolidone mixture, a vinyl acetate/ethylene mixture and a vinyl acetate/dioctyl maleate mixture.
3. A process for producing a conductive composition for a biological electrode as claimed in claim 1, wherein said acid employed as the component (2) is lactic acid, pyrrolidonecarboxylic acid or a combination thereof.
4. A process for producing a conductive composition for a biological electrode as claimed in claim 1, wherein said photopolymerization initiator is selected from the group consisting of benzildimethylketal, 1-hydroxycyclohexyl phenyl ketone, an eutectic mixture of 1-hydroxycyclohexyl phenyl ketone with benzophenone, 2-methyl-1- 4-(methylthio)phenyl!-2-morpholinopropanone-1, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone-1, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, a mixture of 2-hydroxy-2-methyl-1-phenyl-propan-1-one with 2,4,6-trimethylbenzoyldiphenylphosphine oxide, a mixture of 2-hydroxy-2-methyl-1-phenylpropan-1-one with bisacylphosphine oxide, 1- 4-(2-hydroxyethoxy)-phenyl!-2-hydroxy-2-methyl-1-propan-1-one and bis(cyclopentadienyl)-bis(2,6-difluoro-3-(pyr-1-yl)titanium.
5. A process for producing a conductive composition for a biological electrode as claimed in claim 1, wherein said heat polymerization initiator is selected from the group consisting of azobisisobutyronitrile, benzoyl peroxide, lauroyl peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, di-t-amyl peroxide, dicumyl peroxide and t-butyl perbenzoate.
6. A process for producing a conductive composition for a biological electrode as claimed in claim 1, wherein said crosslinking agent is selected from the group consisting of N,N'-methylenebisacrylamide, ethylene glycol dimethacrylate, polyethylene glycol 400 diacrylate, diethylene glycol diacrylate, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, neopentylglycol diacrylate, neopentyl glycol diacryl hydroxypivalate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate and trimethylolpropane trimethacrylate.
7. A process for producing a conductive composition for a biological electrode as claimed in claim 1, wherein the first solution contains an acrylic acid monomer as the unsaturated compound, pyrrolidonecarboxylic acid as the acid giving a moisturizer, N,N'-methylenebisacryletalamide as the crosslinking agent and benzyldimethylketal as the photopolymerization initiator in amounts of from 20 to 50% by weight, from 1 to 43% by weight, from 0.01 to 1% by weight and from 0.01 to 1% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, while the second solution contains water and NaOH in amounts of from 7 to 25% by weight and from 0.2 to 13% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, together with KOH in such an amount as to adjust the pH value of the mixture to 4.0 to 8.0.
8. A process for producing a conductive composition for a biological electrode as claimed in claim 1, wherein the first solution contains an acrylic acid monomer as the unsaturated compound, lactic acid as the acid giving a moisturizer, N,N'-methylenebisacryletalamide as the crosslinking agent and benzyldimethylketal as the photopolymerization initiator in amounts of from 20 to 50% by weight, from 1 to 32% by weight, from 0.01 to 1% by weight and from 0.01 to 1% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, while the second solution contains water and NaOH in amounts of from 10 to 25% by weight and from 0.3 to 32% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, together with KOH in such an amount as to adjust the pH value of the mixture to 4.0 to 8.0.
9. A process for producing a conductive composition for a biological electrode as claimed in claim 1, wherein the first solution contains an acrylic acid monomer as the unsaturated compound, pyrrolidonecarboxylic acid as the acid giving a moisturizer, N,N'-methylenebisacryletalamide as the crosslinking agent and benzyldimethylketal as the photopolymerization initiator in amounts of from 20 to 50% by weight, from 1 to 43% by weight, from 0.01 to 1% by weight and from 0.01 to 1% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, while the second solution contains water in an amount of from 8 to 25% by weight based on the weight of the mixture of the first solution with the second solution and KOH in such an amount as to adjust the pH value of the mixture to 4.0 to 8.0.
10. A process for producing a conductive composition for a biological electrode as claimed in claim 1, wherein the first solution contains an acrylic acid monomer as the unsaturated compound, lactic acid as the acid giving a moisturizer, N-N' methylenebisacryletalamide as the crosslinking agent and benzyldimethylketal as the photopolymerization initiator in amounts of from 20 to 50% by weight, from 1 to 35% by weight, from 0.01 to 1% by weight and from 0.01 to 1% by weight, respectively, each based on the weight of the mixture of the first solution with the second solution, while the second solution contains water in an amount of from 6 to 25% by weight based on the weight of the mixture of the first solution with the second solution and KOH in such an amount as to adjust the pH value of the mixture to 4.0 to 8.0.
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JP19144895A JP3398809B2 (en) | 1995-07-27 | 1995-07-27 | Method for producing conductive composition for bioelectrode |
JP7-191448 | 1995-07-27 |
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US08/687,920 Expired - Fee Related US5821280A (en) | 1995-07-27 | 1996-07-26 | Process for producing conductive composition for biological electrode |
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Cited By (5)
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US6366795B1 (en) * | 1999-05-05 | 2002-04-02 | Biosignal Partners | Biomedical electrode with vital skin penetration |
US6800278B1 (en) | 1996-10-28 | 2004-10-05 | Ballard Medical Products, Inc. | Inherently antimicrobial quaternary amine hydrogel wound dressings |
US11134684B2 (en) | 2005-08-24 | 2021-10-05 | Purdue Research Foundation | Method of using hydrophilized bactericidal polymers |
US11421084B2 (en) | 2017-05-27 | 2022-08-23 | Poly Group LLC | Dispersible antimicrobial complex and coatings therefrom |
US11680116B2 (en) | 2017-06-16 | 2023-06-20 | Poly Group LLC | Polymeric antimicrobial surfactant |
Families Citing this family (3)
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US6262141B1 (en) * | 1999-10-06 | 2001-07-17 | Cytec Technology Corporation | Process for the preparation of polymers having low residual monomer content |
GB0001883D0 (en) * | 2000-01-28 | 2000-03-22 | Ciba Spec Chem Water Treat Ltd | Polymerisation process |
CN113729654B (en) * | 2021-09-14 | 2023-03-28 | 华中科技大学 | Skin-attached sensing system for detecting postoperative skin flap and limb blood flow state reconstruction |
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US4851434A (en) * | 1983-05-27 | 1989-07-25 | Deckner George E | Novel non-irritating moisturizer, compositions containing same and method |
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US4851434A (en) * | 1983-05-27 | 1989-07-25 | Deckner George E | Novel non-irritating moisturizer, compositions containing same and method |
US4666707A (en) * | 1984-04-12 | 1987-05-19 | Kao Corporation | Weakly acidic bath salt composition |
JPH0229328A (en) * | 1988-07-19 | 1990-01-31 | Sumitomo Bakelite Co Ltd | Flexible copper-clad sheet |
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US6800278B1 (en) | 1996-10-28 | 2004-10-05 | Ballard Medical Products, Inc. | Inherently antimicrobial quaternary amine hydrogel wound dressings |
US6366795B1 (en) * | 1999-05-05 | 2002-04-02 | Biosignal Partners | Biomedical electrode with vital skin penetration |
US11134684B2 (en) | 2005-08-24 | 2021-10-05 | Purdue Research Foundation | Method of using hydrophilized bactericidal polymers |
US11459415B2 (en) | 2005-08-24 | 2022-10-04 | Purdue Research Foundation | Method of using hydrophilized bactericidal polymers |
US11421084B2 (en) | 2017-05-27 | 2022-08-23 | Poly Group LLC | Dispersible antimicrobial complex and coatings therefrom |
US11760844B2 (en) | 2017-05-27 | 2023-09-19 | Poly Group LLC | Dispersible antimicrobial complex and coatings therefrom |
US11680116B2 (en) | 2017-06-16 | 2023-06-20 | Poly Group LLC | Polymeric antimicrobial surfactant |
Also Published As
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JPH0938057A (en) | 1997-02-10 |
JP3398809B2 (en) | 2003-04-21 |
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